Connect the primary to mains and use a voltmeter to check you've got 18V ac on each of the secondaries. Power off, hook two secondary wires together to give a centre tap, I'd guess one red, one black. Power up & verify 18V from centre tap to either end. Now check voltage from one end to the other - if the secondaries are in phase you'll have 36V, if the voltage is nowhere near that then swap the wires on one secondary only so the opposite colour is tied to form the centre tap. Recheck voltages to confirm 18V from centre to either end & 36V end to end. Done.

Or wait for a reply from someone who's used these transformers already

So the DCSTB I've bought has the wrong value resistors in locations R1 and R2, 1 ohm resistors are fitted rather than 33.2 ohm Dales (also had some of the transistors in the wrong places but thankfully has never been powered up).
I have some CFR25 Carbon Film 33Ω ±5% 0.33W -1200 → 0ppm/°C, are these suitable to be used instead of the Dales for R1 and R2?

So the DCSTB I've bought has the wrong value resistors in locations R1 and R2, 1 ohm resistors are fitted rather than 33.2 ohm Dales (also had some of the transistors in the wrong places but thankfully has never been powered up).
I have some CFR25 Carbon Film 33Ω ±5% 0.33W -1200 → 0ppm/°C, are these suitable to be used instead of the Dales for R1 and R2?

Uninspiring ppm spec but since that is a constant current position that will bring them to more or less constant working temp you may use them.

Thanks Brakspear, yes that seems the sensible thing to do rather than relying on the bits of sticky tape. Wonder why Toriody don't use different coloured wires like everyone else?

With all the trafos I used from them the output wires were always coming out of the trafo in the same “winding order”, so with red1, red2, blue1, blue2 coming out the inner wires red2, blue1 should be the “center tap”. But measure as stated above to be absolutely sure.

With all the trafos I used from them the output wires were always coming out of the trafo in the same “winding order”, so with red1, red2, blue1, blue2 coming out the inner wires red2, blue1 should be the “center tap”. But measure as stated above to be absolutely sure.